The present invention relates to particular types of alkylbenzene sulfonate surfactant mixtures containing branching and adapted for laundry and cleaning product use by controlling compositional parameters, especially a 2/3-phenyl index and a 2-methyl-2-phenyl index, as well as to improved detergent and cleaning products containing these surfactant mixtures, to alkylbenzene precursors for the surfactant mixtures, and to methods of making the precursors as well as the surfactant mixtures. The present compositions are especially useful for fabric laundering.
Historically, highly branched alkylbenzene sulfonate surfactants, such as those based on tetrapropylene, known as xe2x80x9cABSxe2x80x9d or xe2x80x9cTPBSxe2x80x9d, were used in detergents. However, these were found to be very poorly biodegradable. A long period followed of improving manufacturing processes for alkylbenzene sulfonates, making them as linear as practically possible, hence the acronym xe2x80x9cLASxe2x80x9d. The overwhelming part of a large art of linear alkylbenzene sulfonate surfactant manufacture is directed to this objective. All relevant large-scale commercial alkylbenzene sulfonate processes in use today are directed to linear alkylbenzene sulfonates. However, linear alkylbenzene sulfonates are not without limitations, for example, they would be more desirable if improved for hard water cleaning and/or cold water cleaning properties. They can often fail to produce good cleaning results, for example when formulated with nonphosphate builders and/or when used in hard water areas.
As a result of the limitations of the alkylbenzene sulfonates, consumer cleaning formulations have often needed to include a higher level of cosurfactants, builders, and other additives than would have been needed given a superior alkylbenzene sulfonate.
The art of alkylbenzene sulfonate detergents is replete with references which teach both for and against almost every aspect of these compositions. Moreover, there are believed to be erroneous teachings and technical misconceptions about the mechanism of LAS operation under in-use conditions, particularly in the area of hardness tolerance. The volume of such references debases the art as a whole and makes it difficult to select the useful teachings from the useless without repeated experimentation. To further understand the state of the art, it should be appreciated that there has been not only a lack of clarity on which way to go to fix the unresolved problems of linear LAS, but also a range of misconceptions, not only in the understanding of biodegradation but also in basic mechanisms of operation of LAS in presence of hardness.
Also, while the currently commercial, essentially linear alkylbenzene sulfonate surfactants are relatively simple compositions to define and analyze, compositions containing both branched and linear alkylbenzene sulfonate surfactants are complex. In general such compositions can be highly varied, containing one or more different kinds of branching in any of a number of positions on the aliphatic chain. A very large number, e.g., hundreds, of distinct chemical species are possible in such mixtures. Accordingly there is an onerous burden of experimentation if it is desired to improve such compositions so that they can clean fabrics better in detergent compositions while at the same time remaining biodegradable. The formulator""s knowledge is key to guiding this effort.
Yet another currently unresolved problem in alkylbenzene sulfonate manufacture is to make more effective use of current LAB feedstocks. It would be highly desirable, both from a performance point of view and from an economic point of view, to better utilize certain desirable types of branched hydrocarbons.
Accordingly there is a substantial unmet need for further improvements in alkylbenzene sulfonate surfactant mixtures, especially with respect to those offering one or more of the advantages of superior cleaning, hardness tolerance, satisfactory biodegradability, and cost.
U.S. Pat. Nos. 5,659,099, 5,393,718, 5,256,392, 5,227,558, 5,139,759, 5,164,169, 5,116,794, 4,840,929, 5,744,673, 5,522,984, 5,811,623, 5,777,187, WO 9,729,064, WO 9,747573, WO 9,729,063, U.S. Pat. Nos. 5,026,933; 4,990,718; 4,301,316; 4,301,317; 4,855,527; 4,870,038; 2,477,382; EP 466,558, Jan. 15, 1992; EP 469,940, Feb. 5, 1992; FR 2,697,246, Apr. 29, 1994; SU 793,972, Jan. 7, 1981; U.S. Pat. Nos. 2,564,072; 3,196,174; 3,238,249; 3,355,484; 3,442,964; 3,492,364; 4,959,491; WO 88/07030, Sep. 25, 1990; U.S. Pat. Nos. 4,962,256, 5,196,624; 5,196,625; EP 364,012 B, Feb. 15, 1990; U.S. Pat. Nos. 3,312,745; 3,341,614; 3,442,965; 3,674,885; 4,447,664; 4,533,651; 4,587,374; 4,996,386; 5,210,060; 5,510,306; WO 95/17961, Jul. 6, 1995; WO 95/18084; U.S. Pat. Nos. 5,510,306; 5,087,788; 4,301,316; 4,301,317; 4,855,527; 4,870,038; 5,026,933; 5,625,105 and 4,973,788. The manufacture of alkylbenzene sulfonate surfactants has recently been reviewed. See Vol 56 in xe2x80x9cSurfactant Sciencexe2x80x9d series, Marcel Dekker, New York, 1996, including in particular Chapter 2 entitled xe2x80x9cAlkylarylsulfonates: History, Manufacture, Analysis and Environmental Propertiesxe2x80x9d, pages 39-108 which includes 297 literature references. Surfactant-related analytical methods are described in xe2x80x9cSurfactant Sciencexe2x80x9d series, Vol 73, Marcel Dekker, New York, 1998 and xe2x80x9cSurfactant Sciencexe2x80x9d series, Vol 40, Marcel Dekker, New York, 1992. Documents referenced herein are incorporated in their entirety. See also copending U.S. Patent applications No. 60/053,319 filed on Jul. 21st, 1997, No. 60/053,318, filed on Jul. 21st, 1997, No. 60/053,321, filed on Jul. 21st, 1997, No. 60/053,209, filed on Jul. 21st, 1997, No. 60/053,328, filed on Jul. 21st, 1997, No. 60/053,186, filed on Jul. 21st, 1997 and the art cited therein.
It has now surprisingly been found that there exist certain alkylbenzene sulfonate surfactant mixtures, hereinafter xe2x80x9cmodified alkylbenzene sulfonate surfactant mixturesxe2x80x9d which offer one or more, and even several of the above-outlined advantages. The discovery of these mixtures solves important problems of the kind described in the background.
Thus in accordance with a first embodiment of the present invention, a novel modified alkylbenzene sulfonate surfactant mixture is provided. This novel surfactant mixture comprises, preferably consists essentially of:
(a) from about 15% to about 99%, preferably from about 15% to about 60%, more preferably from about 20% to about 40%, by weight of a mixture of branched alkylbenzene sulfonates having formula (I): 
wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen, the L having two methyl termini and the L having no substituents other than A, R1 and R2; and wherein the mixture of branched alkylbenzene sulfonates contains two or more, preferably at least three, optionally more of the branched alkylbenzene sulfonates differing in molecular weight of the anion of the formula (I) and wherein the mixture of branched alkylbenzene sulfonates has a sum of carbon atoms in R1, L and R2 of from 9 to 15, preferably from 10 to 14; an average aliphatic carbon content, i.e., based on R1, L and R2 and excluding A, of from about 10.0 to about 14.0, preferably from about 11.0 to about 13.0, more preferably from about 11.5 to about 12.5, carbon atoms; M is a cation or cation mixture, preferably selected from H, Na, K, Ca, Mg and mixtures thereof, more preferably selected from H, Na, K and mixtures thereof, more preferably still, selected from H, Na, and mixtures thereof having a valence q, typically from 1 to 2, preferably 1; a and b are integers selected such that the branched alkylbenzene sulfonates are electroneutral, a is typically from 1 to 2, preferably 1, b is 1; R1 is C1-C3 alkyl, preferably C1-C2 alkyl, more preferably methyl; R2 is selected from H and C1-C3 alkyl, preferably H and C1-C2 alkyl, more preferably H and methyl, more preferably H and methyl provided that in at least about 0.5, more preferably 0.7, more preferably 0.9 to 1.0 mole fraction of the branched alkylbenzene sulfonates, R2 is H; A is a benzene moiety, typically A is the moiety xe2x80x94C6H4xe2x80x94, with the SO3 moiety of Formula (1) in para-position to the L moiety, though in some proportion, usually no more than about 5%, preferably from 0 to 5% by weight, the SO3 moiety is ortho- to L; and
(b) from about 1% to about 85%, preferably from about 40% to about 85%, more preferably from about 60% to about 80%, by weight of a mixture of nonbranched alkylbenzene sulfonates having formula (II): 
wherein a, b, M, A and q are as defined hereinbefore and Y is an unsubstituted linear aliphatic moiety consisting of carbon and hydrogen having two methyl termini, and wherein the Y has a sum of carbon atoms of from 9 to 15, preferably from 10 to 14, and the Y has an average aliphatic carbon content of from about 10.0 to about 14.0, preferably from about 11.0 to about 13.0, more preferably 11.5 to 12.5 carbon atoms; and
wherein the modified alkylbenzene sulfonate surfactant mixture is further characterized by a 2/3-phenyl index of from about 160 to about 275, preferably from about 170 to about 265, more preferably from about 180 to about 255; and also preferably wherein the modified alkylbenzene sulfonate surfactant mixture has a 2-methyl-2-phenyl index of less than about 0.3, preferably less than about 0.2, more preferably less than about 0.1, more preferably still, from 0 to 0.05.
In accordance with a second embodiment of present invention, a novel surfactant mixture is provided. This novel surfactant mixture comprises, preferably consisting essentially of the product of a process comprising the steps of:
(I) alkylating benzene with an alkylating mixture in the presence of a zeolite beta catalyst;
(II) sulfonating the product of (I); and, optionally, but very preferably
(III) neutralizing the product of (II);
wherein the alkylating mixture comprises:
(a) from about 1% to about 99.9%, by weight of branched C9-C20, preferably C9-C15, more preferably C10-C14 monoolefins, the branched monoolefins having structures identical with those of the branched monoolefins formed by dehydrogenating branched paraffins of formula R1LR2 wherein L is an acyclic aliphatic moiety consisting of carbon and hydrogen and containing two terminal methyls; R1 is C1 to C3 alkyl; and R2 is selected from H and C1 to C3 alkyl; and
(b) from about 0.1% to about 85%, by weight of C9-C20, preferably C9-C15, more preferably C10-C14 linear aliphatic olefins;
wherein the alkylating mixture contains the branched C9-C20 monoolefins having at least two different carbon numbers in the C9-C20 range, and has a mean carbon content of from about 9.0 to about 15.0, preferably from about 10.0 to about 14.0, more preferably from about 1.0 to about 13.0, more preferably still from about 11.5 to about 12.5 carbon atoms; and wherein the components (a) and (b) are at a weight ratio of at least about 15:85.
In accordance with a third embodiment of present invention, a novel surfactant mixture is provided. This novel surfactant mixture consists essentially of the product of a process comprising the steps, in sequence, of:
(I) alkylating benzene with an alkylating mixture in the presence of a zeolite beta catalyst;
(II) sulfonating the product of (I); and
(III) neutralizing the product of (II);
wherein the alkylating mixture comprises:
(a) from about 1% to about 99.9%, by weight of a branched alkylating agent selected from:
(i) C9-C20 (preferably C9-C15, more preferably C10-C14) internal monoolefins R1LR2 wherein L is an acyclic olefinic moiety consisting of carbon and hydrogen and containing two terminal methyls;
(ii) C9-C20 (preferably C9-C15, more preferably C10-C14) alpha monoolefins R1AR2 wherein A is an acyclic alpha-olefinic moiety consisting of carbon and hydrogen and containing one terminal methyl and one terminal olefinic methylene;
(iii) C9-C20 (preferably C9-C15, more preferably C10-C14) vinylidene monoolefins R1BR2 wherein B is an acyclic vinylidene olefin moiety consisting of carbon and hydrogen and containing two terminal methyls and one internal olefinic methylene;
(iv) C9-C20 (preferably C9-C15, more preferably C10-C14) primary alcohols R1QR2 wherein Q is an acyclic aliphatic primary terminal alcohol moiety consisting of carbon, hydrogen and oxygen and containing one terminal methyl;
(v) C9-C20 (preferably C9-C15, more preferably C10-C14) primary alcohols R1ZR2 wherein Z is an acyclic aliphatic primary nonterminal alcohol moiety consisting of carbon, hydrogen and oxygen and containing two terminal methyls; and
(vi) mixtures thereof;
wherein in any of (i)-(vi), the R1 is C1 to C3 alkyl and the R2 is selected from H and C1 to C3 alkyl; and
(b) from about 0.1% to about 85%, by weight of C9-C20 (preferably C9-C15, more preferably C10-C14) linear alkylating agent selected from C9-C20 (preferably C9-C15 more preferably C10-C14) linear aliphatic olefins, C9-C20 (preferably C9-C15, more preferably C10-C14) linear aliphatic alcohols and mixtures thereof;
wherein the alkylating mixture contains the branched alkylating agents having at least two different carbon numbers in the C9-C20 (preferably C9-C15, more preferably C10-C14) range, and has a mean carbon content of from about 9.0 to about 15.0 carbon atoms (preferably from about 10.0 to about 14.0, more preferably from about 11.0 to about 13.0, more preferably still from about 11.5 to about 12.5); and wherein the components (a) and (b) are at a weight ratio of at least about 15:85 (preferably having linear component (b) in excess of branched component (a), for example 51% or more by weight of (b) and 49% or less of (a), more preferably 55% to 85% by weight of (b) and 15% to 45% of (a), more preferably still 60% to 80% by weight of (b) and 20% to 40% of (a) wherein these percentages by weight exclude any other materials, for example diluent hydrocarbons, that may be present in the process).
In accordance with a fourth embodiment of present invention, a novel detergent composition is provided. This novel detergent composition comprising, preferably consisting essentially of:
(a) from about 0.1% to about 50%, preferably from about 0.5% to about 40%, more preferably from about 1% to about 35%, by weight of a linear alkylbenzene sulfonate surfactant mixture having a 2/3-phenyl index of from about 160 to about 275, preferably from about 170 to about 265, more preferably from about 180 to about255;
(b) from about 0.1% to about 99.9%, preferably from about 5% to about 98%, more preferably from about 50% to about 95%), by weight of conventional cleaning adjuncts other than surfactants; and
(c) from 0% to about 50%, in some preferred embodiments, 0%, and in others preferably from about 0.1% to about 30%, more typically from about 0.2% to about 10%, by weight of a surfactant other than the linear alkylbenzene sulfonate surfactant mixture;
provided that when the detergent composition comprises any other alkylbenzene sulfonate than the alkylbenzene sulfonate of the linear alkylbenzene sulfonate surfactant mixture, the linear alkylbenzene sulfonate surfactant mixture and the other alkylbenzene sulfonate, as a mixture, have an overall 2/3-phenyl index of from about 160 to about 275, preferably from about 170 to about 265, more preferably from about 180 to about 255.
The present invention is also directed to detergent compositions comprising the surfactant mixtures of embodiments one, two and three as well as conventional detergent adjuncts. The present invention also is directed to methods of cleaning using these compositions.
The preferred cleaning composition embodiments also contain specific cleaning additives, defined hereafter.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
The present invention relates to novel surfactant compositions. It also relates to novel cleaning compositions containing the novel surfactant system and methods of cleaning using the cleaning compositions.
In accordance with the first embodiment one preferred surfactant mixture comprises: a mixture of the branched alkylbenzene sulfonates and nonbranched alkylbenzene sulfonates, wherein the 2-methyl-2-phenyl index of the modified alkylbenzene sulfonate surfactant mixture is less than about 0.05, and wherein in the mixture of branched and nonbranched alkylbenzene sulfonates, the average aliphatic carbon content is from about 11.5 to about 12.5 carbon atoms; the R1 is methyl; the R2 is selected from H and methyl provided that in at least about 0.7 mole fraction of the branched alkylbenzene sulfonates R2 is H; and wherein the sum of carbon atoms in R1, L and R2 is from 10 to 14; and further wherein in the mixture of nonbranched alkylbenzene sulfonates, the Y has a sum of carbon atoms of from 10 to 14 carbon atoms, the average aliphatic carbon content of the nonbranched alkylbenzene sulfonates is from about 11.5 to about 12.5 carbon atoms, and the M is a monovalent cation or cation mixture selected from H, Na and mixtures thereof
In accordance with the second embodiment one preferred alkylating mixture comprises:
(a) from about 0.5% to about 47.5%, by weight of said branched alkylating agent selected from:
(i) C9-C14 internal monoolefins R1LR2 wherein L is an acyclic olefinic moiety consisting of carbon and hydrogen and containing two terminal methyls;
(ii) C9-C14 alpha monoolefins R1AR2 wherein A is an acyclic alpha-olefinic moiety consisting of carbon and hydrogen and containing one terminal methyl and one terminal olefinic methylene; and
(iii) mixtures thereof;
wherein in any of (i)-(iii), said R1 is methyl, and said R2 is H or methyl provided that in at least about 0.7 mole fraction of the total of said monoolefins, R2 is H; and
(b) from about 0.1% to about 25%, by weight of C9-C14 linear aliphatic olefins; and
(c) from about 50% to about 98.9%, by weight of carrier materials selected from paraffins and inert nonparaffinic solvents;
wherein said alkylating mixture contains said branched alkylating agents having at least two different carbon numbers in said C9-C14 range, and has a mean carbon content of from about 11.5 to about 12.5 carbon atoms; and wherein said components (a) and (b) are at a weight ratio of from about 20:80 to about 49:51.
Preferably the surfactant mixtures according to the present invention also have a 2-methyl-2-phenyl index of less than about 0.3, more preferably less than about 0.2, even more preferably less than about 0.1, even more preferably still, from 0 to 0.05.
Definitions
Methyl termini The terms xe2x80x9cmethyl terminixe2x80x9d and/or xe2x80x9cterminal methylxe2x80x9d mean the carbon atoms which are the terminal carbon atoms in alkyl moieties, that is L, and/or Y of formula (I) and formula (II) respectively are always bonded to three hydrogen atoms. That is, they will form a CH3xe2x80x94 group. To better explain this, the structure below shows the two terminal methyl groups in an alkylbenzene sulfonate. 
The term xe2x80x9cABxe2x80x9d herein when used without further qualification is an abbreviation for xe2x80x9calkylbenzenexe2x80x9d of the so-called xe2x80x9chardxe2x80x9d or nonbiodegradable type which on sulfonation forms xe2x80x9cABSxe2x80x9d. The term xe2x80x9cLABxe2x80x9d herein is an abbreviation for xe2x80x9clinear alkylbenzenexe2x80x9d of the current commercial, more biodegradable type, which on sulfonation forms linear alkylbenzene sulfonate, or xe2x80x9cLASxe2x80x9d. The term xe2x80x9cMLASxe2x80x9d herein is an abbreviation for the modified alkylbenzene sulfonate mixtures of the invention.
Impurities: The surfactant mixtures herein are preferably substantially free from impurities selected from tribranched impurities, dialkyl tetralin impurities and mixtures thereof. By xe2x80x9csubstantially freexe2x80x9d it is meant that the amounts of such impurities are insufficient to contribute positively or negatively to the cleaning effectiveness of the composition. Typically there is less than about 5%, preferably less than about 1%, more preferably about 0.1% or less of the impurity, that is typically no one of the impurities is practically detectable.
Illustrative Structures
The better to illustrate the possible complexity of modified alkylbenzene sulfonate surfactant mixtures of the invention and the resulting detergent compositions, structures (a) to (v) below are illustrative of some of the many preferred compounds of formula (I). These are only a few of hundreds of possible preferred structures that make up the bulk of the composition, and should not be taken as limiting of the invention. 
Structures (w) and (x) nonlimitingly illustrate less preferred compounds of Formula (I) which can be present, at lower levels than the above-illustrated preferred types of stuctures, in the modified alkylbenzene sulfonate surfactant mixtures of the invention and the resulting detergent compositions. 
Structures (y), (z), and (aa) nonlimitingly illustrate compounds broadly within Formula (I) that are not preferred but which can be present in the modified alkylbenzene sulfonate surfactant mixtures of the invention and the resulting detergent compositions. 
Structure (bb) is illustrative of a tri-branched structure not within Formula (I), but that can be present as an impurity.
Preferably the branched alkylbenzene sulfonate is the product of sulfonating a branched alkylbenzene, wherein the branched alkylbenzene is produced by alkylating benzene with a branched olefin over an zeolite beta catalyst which may be fluoridated or non-fluoridated, more preferably the zeolite beta catalyst is an acidic zeolite beta catalyst. The preferred acidic zeolite beta catalysts are HF-treated calcined zeolite beta catalysts.
In outline, modified alkylbenzene sulfonate surfactant mixtures herein can be made by the steps of:
(I) alkylating benzene with an alkylating mixture;
(II) sulfonating the product of (I); and (optionally but very preferably)
(III) neutralizing the product of (II).
Provided that suitable alkylation catalysts and process conditions as taught herein are used, the product of step (I) is a modified alkylbenzene mixture in accordance with the invention. Provided that sulfonation is conducted under conditions generally known and reapplicable from LAS manufacture, see for example the literature references cited herein, the product of step (II) is a modified alkylbenzene sulfonic acid mixture in accordance with the invention. Provided that neutralization step (III) is conducted as generally taught herein, the product of step (III) is a modified alkylbenzene sulfonate surfactant mixture in accordance with the invention. Since neutralization can be incomplete, mixtures of the acid and neutralized forms of the present modified alkylbenzene sulfonate systems in all proportions, e.g., from about 1000:1 to 1:1000 by weight, are also part of the present invention. Overall, the greatest criticalities are in step (I).
Thus it is further preferred that in step (I) the alkylation is performed at a temperature of from about 125xc2x0 C. to about 230xc2x0 C., preferably from about 175xc2x0 C. to about 215xc2x0 C. and at a pressure of from about 50 psig to about 1000 psig, preferably from about 100 psig to about 250 psig. Time for this alkylation reaction can vary, however it is further preferred that the time for this alkylation be from about 0.01 hour to about 18 hours, more preferably, as rapidly as possible, more typically from about 0.1 hour to about 5 hours, or from about 0.1 hour to about 3 hours.
In general it is found preferable in step (I) to couple together the use of relatively low temperatures (e.g., 175xc2x0 C. to about 215xc2x0 C.) with reaction times of medium duration (1 hour to about 8 hours) in the above-indicated ranges.
Moreover, it is contemplated that the alkylation xe2x80x9cstepxe2x80x9d (I) herein can be xe2x80x9cstagedxe2x80x9d so that two or more reactors operating under different conditions in the defined ranges may be useful. By operating a plurality of such reactors, it is possible to allow for material with less preferred 2-methyl-2-phenyl index to be initially formed and, surprisingly, to convert such material into material with a more preferred 2-methyl-2-phenyl index.
Thus a surprising discovery as part of the present invention is that one can attain low levels of quaternary alkylbenzenes in zeolite beta catalyzed reactions of benzene with branched olefins, as characterized by a 2-methyl-2-phenyl index of less than 0.1.
Alkylation Catalyst
The present invention uses a particularly defined alkylation catalyst. Such catalyst comprises a moderate acidity, medium-pore zeolite defined in detail hereinafter. A particularly preferred alkylation catalyst comprises at least partially dealuminized acidic nonfluoridated or at least partially dealuminized acidic fluoridated zeolite beta.
Numerous alkylation catalysts are readily determined to be unsuitable. Unsuitable alkylation catalysts include the DETAL(copyright) process catalysts, aluminum chloride, HF, and many others. Indeed no alkylation catalyst currently used for alkylation in the commercial production of detergent linear alkylbenzenesulfonates is suitable.
In contrast, suitable alkylation catalyst herein is selected from shape-selective moderately acidic alkylation catalysts, preferably zeolitic. More particularly, the zeolite in such catalysts for the alkylation step step I is preferably selected from the group consisting of ZSM-4, ZSM-20, and zeolite beta, more preferably zeolite beta, in at least partially acidic form. More preferably, the zeolite in step I (the alkylation step) is substantially in acid form and is contained in a catalyst pellet comprising a conventional binder and further wherein said catalyst pellet comprises at least about 1%, more preferably at least 5%, more typically from 50% to about 90%, of said zeolite, wherein said zeolite is preferably a zeolite beta. More generally, suitable alkylation catalyst is typically at least partially crystalline, more preferably substantially crystalline not including binders or other materials used to form catalyst pellets, aggregates or composites. Moreover the catalyst is typically at least partially acidic zeolite beta. This catalyst is useful for the alkylation step identified as step I in the claims hereinafter.
The largest pore diameter characterizing the zeolites useful in the present alkylation process may be in the range of 6 Angstrom to 8 Angstrom, such as in zeolite beta. It should be understood that, in any case, the zeolites used as catalysts in the alkylation step of the present process have a major pore dimension intermediate between that of the large pore zeolites, such as the X and Y zeolites, and the relatively smaller pore size zeolites such as mordenite, offretite, HZSM-12 and HZSM-5. Indeed ZSM-5 has been tried and found inoperable in the present invention. The pore size dimensions and crystal structures of certain zeolites are specified in ATLAS OF ZEOLITE STRUCTURE TYPES by W. M. Meier and D. H. Olson, published by the Structure Commission of the International Zeolite Association (1978 and more recent editions) and distributed by Polycrystal Book Service, Pittsburgh, Pa.
The zeolites useful in the alkylation step of the instant process generally have at least 10 percent of the cationic sites thereof occupied by ions other than alkali or alkaline-earth metals. Typical but non-limiting replacing ions include ammonium, hydrogen, rare earth, zinc, copper and aluminum. Of this group, particular preference is accorded ammonium, hydrogen, rare earth or combinations thereof. In a preferred embodiment, the zeolites are converted to the predominantly hydrogen form, generally by replacement of the alkali metal or other ion originally present with hydrogen ion precursors, e.g., ammonium ions. which upon calcination yield the hydrogen form. This exchange is conveniently carried out by contact of the zeolite with an ammonium salt solution, e.g., ammonium chloride, utilizing well known ion exchange techniques. In certain preferred embodiments, the extent of replacement is such as to produce a zeolite material in which at least 50 percent of the cationic sites are occupied by hydrogen ions.
The zeolites may be subjected to various chemical treatments, including alumina extraction (dealumination) and combination with one or more metal components, particularly the metals of Groups IIB, III, IV, VI, VII and VIII. It is also contemplated that the zeolites may, in some instances, desirably be subjected to thermal treatment, including steaming or calcination in air, hydrogen or an inert gas, e.g. nitrogen or helium.
A suitable modifying treatment entails steaming of the zeolite by contact with an atmosphere containing from about 5 to about 100% steam at a temperature of from about 250xc2x0 C. to 1000xc2x0 C. Steaming may last for a period of between about 0.25 and about 100 hours and may be conducted at pressures ranging from sub-atmospheric to several hundred atmospheres.
In practicing the desired alkylation step of the instant process, it may be useful to incorporate the above-described intermediate pore size crystalline zeolites in another material, e.g., a binder or matrix resistant to the temperature and other conditions employed in the process. Such matrix materials include synthetic or naturally occurring substances as well as inorganic materials such as clay, silica, and/or metal oxides. Matrix materials can be in the form of gels including mixtures of silica and metal oxides. The latter may be either naturally occurring or in the form of gels or gelatinous precipitates. Naturally occurring clays which can be composited with the zeolite include those of the montmorillonite and kaolin families, which families include the sub-bentonites and the kaolins commonly known as Dixie, McNamee-Georgia and Florida clays or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. Such clays can be used in the raw state as originally mined or initially subjected to calcination, acid treatment or chemical modification.
In addition to the foregoing materials, the intermediate pore size zeolites employed herein may be compounded with a porous matrix material, such as alumina, silica-alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia, and silica-titania, as well as ternary combinations, such as silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia and silica-magnesia-zirconia. The matrix may be in the form of a cogel. The relative proportions of finely divided zeolite and inorganic oxide gel matrix may vary widely, with the zeolite content ranging from between about 1 to about 99% by weight and more usually in the range of about 5 to about 80% by weight of the composite.
A group of zeolites which includes some useful for the alkylation step herein have a silica:alumina ratio of at least 10:1, preferably at least 20:1. The silica:alumina ratios referred to in this specification are the structural or framework ratios, that is, the ratio for the SiO4 to the AlO4 tetrahedra. This ratio may vary from the silica:alumina ratio determined by various physical and chemical methods. For example, a gross chemical analysis may include aluminum which is present in the form of cations associated with the acidic sites on the zeolite, thereby giving a low silica:alumina ratio. Similarly, if the ratio is determined by thermogravimetric analysis (TGA) of ammonia desorption, a low ammonia titration may be obtained if cationic aluminum prevents exchange of the ammonium ions onto the acidic sites. These disparities are particularly troublesome when certain treatments such as the dealuminization methods described below which result in the presence of ionic aluminum free of the zeolite structure are employed. Due care should therefore be taken to ensure that the framework silica:alumina ratio is correctly determined.
When the zeolites have been prepared in the presence of organic cations they are catalytically inactive, possibly because the intracrystalline free space is occupied by organic cations from the forming solution. They may be activated by heating in an inert atmosphere at 540xc2x0 C. for one hour, for example, followed by base exchange with ammonium salts followed by calcination at 540xc2x0 C. in air. The presence of organic cations in the forming solution may not be absolutely essential to the formation of the zeolite; but it does appear to favor the formation of this special type of zeolite. Some natural zeolites may sometimes be converted to zeolites of the desired type by various activation procedures and other treatments such as base exchange, steaming, alumina extraction and calcination. The zeolites preferably have a crystal framework density, in the dry hydrogen form, not substantially below about 1.6 g.cm-3. The dry density for known structures may be calculated from the number of silicon plus aluminum atoms per 1000 cubic Angstroms, as given, e.g., on page 19 of the article on Zeolite Structure by W. M. Meier included in xe2x80x9cProceedings of the Conference on Molecular Sieves, London, April 1967xe2x80x9d, published by the Society of Chemical Industry, London, 1968. Reference is made to this paper for a discussion of the crystal framework density. A further discussion of crystal framework density, together with values for some typical zeolites, is given in U.S. Pat. No. 4,016,218, to which reference is made. When synthesized in the alkali metal form, the zeolite is conveniently converted to the hydrogen form, generally by intermediate formation of the ammonium form as a result of ammonium ion exchange and calcination of the ammonium form to yield the hydrogen form. It has been found that although the hydrogen form of the zeolite catalyzes the reaction successfully, the zeolite may also be partly in the alkali metal form.
Prefered zeolite catalysts include zeolite beta, HZSM-4, HZSM-20 and HZSM-38. Most prefered catalyst is acidic zeolite beta. A zeolite beta suitable for use herein is disclosed in U.S. Pat. No. 3,308,069 to which reference is made for details of this zeolite and its preparation.
Zeolite beta catalysts in the acid form are also commercially available as Zeocat PB/H from Zeochem. Other zeolite beta catalysts suitable for use can be provided by UOP Chemical Catalysts and Zeolyst International.
Most generally, alkylation catalysts may be used herein provided that the alkylation catalyst 1) can accommodate into the smallest pore diameter of said catalyst said branched olefins described herein and 2) selectively alkylate benzene with said branched olefins and/or mixture with nonbranched olefins with sufficient selectivity to provide the 2/3-Ph index values defined herein.
In one preferred mode, a hydrotrope or hydrotrope precursor is added either after step (I). during or after step (II) and prior to step (III) or during or after step (m). The hydrotropes are selected from any suitable hydrotrope, typically a sulfonic acid or sodium sulfonate salt of toluene, cumene, xylene, napthalene or mixtures thereof. The hydrotropes precursors are selected from any suitable, hydrotrope precursor typically toluene, cumene, xylene, napthalene or mixtures thereof.
Sulfonation and Workup or Neutralization (Steps II/III)
Preferably the sulfonating step (II) is performed using a sulfonating agent, preferably selected from the group consisting of sulfuric acid, sulfur trioxide with or without air, chlorosulfonic acid, oleum, and mixtures thereof. Furthermore, it is preferable in step (II) to remove components other than monoalkylbenzene prior to contacting the product of step (I) with sulfonating agent.
In general, sulfonation of the modified alkylbenzenes in the instant process can be accomplished using any of the well-known sulfonation systems, including those described in xe2x80x9cDetergent Manufacture Including Zeolite Builders and other New Materialsxe2x80x9d, Ed. Sittig., Noyes Data Corp., 1979, as well as in Vol. 56 in xe2x80x9cSurfactant Sciencexe2x80x9d series, Marcel Dekker, New York, 1996, including in particular Chapter 2 entitled xe2x80x9cAlkylarylsulfonates: History, Manufacture, Analysis and Environmental Propertiesxe2x80x9d, pages 39-108 which includes 297 literature references. This work provides access to a great deal of literature describing various processes and process steps, not only sulfonation but also dehydrogenation, alkylation, alkylbenzene distillation and the like. Common sulfonation systems useful herein include sulfuric acid, chlorosulfonic acid, oleum, sulfur trioxide and the like. Sulfur trioxide/air is especially preferred. Details of sulfonation using a suitable air/sulfur trioxide mixture are provided in U.S. Pat. No. 3,427,342, Chemithon. Sulfonation processes are further extensively described in xe2x80x9cSulfonation Technology in the Detergent Industryxe2x80x9d, W. H. de Groot, Kluwer Academic Publishers, Boston, 1991.
Any convenient workup steps may be used in the present process. Common practice is to neutralize after sulfonation with any suitable alkali. Thus the neutralization step can be conducted using alkali selected from sodium, potassium, ammonium, magnesium and substituted ammonium alkalis and mixtures thereof. Potassium can assist solubility, magnesium can promote soft water performance and substituted ammonium can be helpful for formulating specialty variations of the instant surfactants. The invention encompasses any of these derivative forms of the modified alkylbenzenesulfonate surfactants as produced by the present process and their use in consumer product compositions.
Alternately the acid form of the present surfactants can be added directly to acidic cleaning products, or can be mixed with cleaning ingredients and then neutralized.
Preferably the neutralisation step (III) is performed using a basic salt. Preferably the basic salt having a cation selected from the group consisting of alkali metal, alkaline earth metal, ammonium, substituted ammonium, and mixtures thereof and an anion selected from hydroxide, oxide, carbonate, silicate, phosphate and mixtures thereof. More preferably the basic salt is selected from the group consisting of sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonium hydroxide, and mixtures thereof.
The processes are tolerant of variation, for example conventional steps can be added before, in parallel with, or after the outlined steps (I), (II) and (III). This is especially the case for accomodating the use of hydrotropes or their precursors.